Marine Archaeon Methanosarcina acetivorans Enhances Polyphosphate Metabolism Under Persistent Cadmium Stress

Abstract

Phosphate metabolism was studied to determine whether polyphosphate (polyP) pools play a role in the enhanced resistance against Cd2+ and metal-removal capacity of Cd2+-preadapted (CdPA) Methanosarcina acetivorans. Polyphosphate kinase (PPK), exopolyphosphatase (PPX) and phosphate transporter transcript levels and their activities increased in CdPA cells compared to control (Cnt) cells. K+ inhibited recombinant Ma-PPK and activated Ma-PPX, whereas divalent cations activated both enzymes. Metal-binding polyP and thiol-containing molecule contents, Cd2+-removal, and biofilm synthesis were significantly higher in CdPA cells >Cnt cells plus a single addition of Cd2+>Cnt cells. Also, CdPA cells showed a higher number of cadmium, sulfur, and phosphorus enriched-acidocalcisomes than control cells. Biochemical and physiological phenotype exhibited by CdPA cells returned to that of Cnt cells when cultured without Cd2+. Furthermore, no differences in the sequenced genomes upstream and downstream of the genes involved in Cd2+ resistance were found between CdPA and Cnt cells, suggesting phenotype loss rather than genome mutations induced by chronic Cd2+-exposure. Instead, a metabolic adaptation induced by Cd2+ stress was apparent. The dynamic ability of M. acetivorans to change its metabolism, depending on the environmental conditions, may be advantageous to remove cadmium in nature and biodigesters.

Unraveling the multifaceted resilience of arsenic resistant bacterium Deinococcus indicus

“…This high heterogeneity reveals high plasticity in PolyP granules of D. indicus cells, and could indicate that cells adopt specific roles in the community, specializing in PolyP storage to gain an advantage upon environmental changes. pPLGs are also known to be involved in heavy-metal detoxification ( Pan-Hou et al, 2001 , 2002 ; Alvarez and Jerez, 2004 ; Ruiz et al, 2011 ; Orell et al, 2012 ; Jasso-Chávez et al, 2019 ; Sanz-Luque et al, 2020 ). In Anabaena cylindrica a higher accumulation of aluminum was observed on cells exhibiting pPLGs that were grown in a phosphate-rich medium ( Annette et al, 1985 ).…”

Syntrophy between bacteria and archaea enhances methane production in an EGSB bioreactor fed by cheese whey wastewater

“…For example, when exposed to stress conditions, Methanosarcina acetivorans increases the synthesis of metabolites, such as methane, HS-CoM (2-mercaptoethanesulfonate or Coenzyme M), polyphosphate, glycogen, and biofilms. In addition, pre-adaptation to stress conditions helps to increase the synthesis of metabolites (Jasso-Chávez et al, 2019). Methanosarcina spelaei RK-23, a recent methanogen isolated from anaerobic digestor, was the first methanogen reported with the unique ability to secrete bioflocculants (biosurfactants) (Zhao et al, 2020).…”

Using genome comparisons of wild-type and resistant mutants of Methanococcus maripaludis to help understand mechanisms of resistance to methane inhibitors

“…Four SNP mutations were found in resistant strains of Methanobrevibacter smithii , three of them in hypothetical proteins and one in a potassium transporter. In another study investigating cadmium resistance in Methanosarcina acetivorans , no genetic changes were found, suggesting that metabolic changes as sufficient to explain the observed resistance [ 25 ]. Despite the promising outlook for the use of inhibitors in controlling methane emissions, the effects of these compounds on animal health, food safety and environmental impact remain a significant concern.…”